Dual wheel assembly and clamp therefor

ABSTRACT

A wheel assembly suitable for supporting dual tires comprises a wheel having an inboard shoulder against which a rim assembly for the tires can be clamped. The wheel has outboard peripherally spaced spokes each having a rim clamp fastened thereto. The wheel is modified from conventional wheels by reason of extensions formed on the outboard ends of said spokes. The rim clamp is conventional in that it has a leg portion beveled for wedging against an outboard rim shoulder, but is modified from conventional rim clamps by reason of having a second leg sized to seat upon the aforementioned spoke extensions.

United States Patent Durham [451 July 11,1972

[72] Inventor: Nolan B. Durham, Miamisburg, Ohio [73] Assignee: CroweManufacturing Company, Dayton,

Ohio a part interest [22] Filed: Jan. 22, 1970 [21] Appl.No.: 4,925

1,946,171 2/1934 Miller ..301/13 SM X 1,790,421 1/1931 Holt ..301/203,142,516 7/1964 Durham ..301/13 SM Primary Examiner-Richard J. JohnsonAttorney-Dybvig & Dybvig [57] ABSTRACT A wheel assembly suitable forsupporting dual tires comprises a wheel having an inboard shoulderagainst which a rim assembly for the tires can be clamped. The wheel hasoutboard peripherally spaced spokes each having a rim clamp fastenedthereto. The wheel is modified from conventional wheels by reason ofextensions formed on the outboard ends of said spokes. The rim clamp isconventional in that it has a leg portion beveled for wedging against anoutboard rim shoulder, but is modified from conventional rim clamps byreason of having a second leg sized to seat upon the aforementionedspoke extensions.

3 Claims, 5 Drawing Figures BACKGROUND OF THE INVENTION This inventionrelates to a dual wheel assembly and more particularly to an improvedrim clamp construction for use in securing dual rims on a wheel member.The invention is an improvement to the dual wheel assembly illustratedin my U.S. Pat. No. 3,142,516 issued July 28, 1964.

One object of the present invention is to provide a new and improved rimclamp for securing the rims of dual wheel assemblies.

Another object of the present invention is to provide a new and improvedspoke design for use in combination with the rim clamp of the presentinvention.

Other objects and advantages reside in the construction of parts, thecombination thereof, the method of manufacture and the mode ofoperation, as will be more apparent in the following description.

SUMMARY OF TI-IE INVENTION A vast number of difierent types of rimclamps and associated dual wheel assemblies can be found in the priorart. Only a few of this vast number have met with commercial successand, insofar as known, none have solved the basic problems to which thepresent invention is addressed. One basic problem resides in a tendencyof the clamp to press the rim into a cocked position such that the axisof the rim is not coaxial to the axis of the wheel and accordingly atire mounted on the rim does not track uniformly on the roadway. Thisleads to excessive tire wear. A second related problem is the tendencyof the clamp itself to assume a cocked position. When this happens theclamp may be jarred to its uncooked position during use with the resultthat an inadequate pressure is thereafter applied to the rim assembly.When this happens, the wheel member which supports the rim assembly hasa tendency to spin within the rim assembly with the result that aninadequate torque is applied to the tires. This inadequate torque canbecome manifest both on acceleration and deceleration.

The rim clamp of my aforementioned patent was designed to overcome thesebasic problems but has thus far proved too expensive and time-consumingin assembly to promote widespread use by the trucking industry. The dualwheel assembly of the present invention has been devised to preserve thebasic merit of the structure disclosed in my aforementioned patent andalso to eliminate disadvantageous cost features of my patentedstructure. To reduce raw material costs the rim clamp has beenredesigned from a U-shape to an L- shape thus eliminating nearly halfthe steel required to produce the clamp. The L-shape also simplifies theassembly of the clamp to a wheel spoke and thus reduces the labor costsin assembling the clamps to the dual wheel structure.

The U-shape clamp assured proper alignment of the wheel clamp onto thewheel spoke. To achieve the same assurance with the L-shape clampstructure of the present invention, the wheel spokes have been providedwith axial outboard extensions which, as will be later explained ingreater detail, cooperate with one leg of the L-shape clamp to assurethat the clamp and rim assembly will not be assembled in a cookedposition.

DESCRIPTION OF THE DRAWING In the drawing, FIG. 1 is a section view witha portion cut away illustrating the dual wheel assembly which is morefully disclosed in my aforementioned patent.

FIG. 2 is an enlarged perspective view of my prior art wheel clamp.

FIG. 3 is a fragmentary sectional view analogous to that of FIG. 1illustrating the improvement of the present invention.

FIG. 4 is an enlarged perspective view of my improved wheel clamp.

FIG. 5 is a fragmentary and enlarged sectional view taken substantiallyalong the line 5-5 of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawing in greaterdetail, reference numeral 10 designates the wheel member of my prior artwheel assembly. This wheel member is characterized by having aconventional radially enlarged shoulder 12 against which the rimassembly is to be aligned. The wheel member 10 is also characterized byan annular or cylindrical surface portion 14 which serves to guide therim assembly into proper position upon the wheel member.

The wheel member is further characterized by a plurality of axiallyextending spokes 16. It is conventional in the art to refer to the sideof the wheel member 10 at which the shoulder 12 is located as theinboard side of the wheel member. Likewise, it is conventional in theart to refer to the side of the wheel member 10 at which the spoke 16 islocated as the outboard side of the wheel member. It has also becomeconventional in the wheel constructions of the type illustrated in FIG.1 to employ a total of five peripherally spaced spokes on the outboardside of the wheel member 10. This means of course that five rim clampsare intended to be used in securing an assembly of rims onto the wheelmember 10.

The rim assembly of FIG. 1 comprises a first rim 20 adapted to supportan inboard tire, a second rim 26 adapted to support an outboard tire,and an annular spacer 24 interposed between the rims 20 and 26 to assurea desired spacing between the inboard and outboard tires.

The inboard rim 20 is equipped with a radially inwardly directedshoulder 22 designed to interfit and snugly abut the wheel shoulder 12.The outboard rim 26 is equipped with a similar radially inwardlydirected shoulder 28 which is adapted to interfit a conically shapedsurface 32 located on my prior art clamp 18.

It is evident from an inspection of FIG. 1 that my prior art dual wheelis assembled as follows. The inboard rim 20 is first slid over the wheelmember 10 to the inboard position illustrated in FIG. 1. The spokes l6assist this operation by guiding the rim 20 into concentric relationwith the wheel member 10. The spacer 24 is next slid to the positionillustrated in FIG. 1 and the outboard rim 26 then guided by the spokes16 to abutment with the spacer 24. The clamps 18, only one being shownin FIG. 2, are then fitted on the outboard ends of the spokes 16. Itwill be noted that the clamps 18 have apertures 36 therein whichaccommodate bolts 38 fixedly embedded in the spokes 16. The dual wheelassembly is completed by turning threaded nuts 40 onto threaded ends ofthe bolts 38 and in so doing driving the clamps 18 in the inboarddirection so as to clamp the rim assembly between the wheel shoulder 12on the inboard side and the surfaces 32 of the clamps 18 on the outboardside.

It will be noted that the clamp 18 has a cylindrically curved leg 33 andthe curvature of this leg is adapted to match the curvature of the uppersurface of the spoke 16, as viewed in FIG. 1. Likewise, the clamp 18 hasan opposite leg 30 adapted to interfit a cylindrical curved undersurfaceof the spoke 16, as viewed in FIG. 1. These cylindrically curvedsurfaces of the clamp 18 are held in fixed spaced relation by the endsurface 34 of the clamp 18 which includes the aperture 36. It is thefixed spacing between these cylindrically curved surfaces of the clamp18 and their interfitting relation to the spokes 16 that assuresassembly of the dual wheel of FIG. 1 without encountering the cocked rimcondition which has proved so vexatious to the trucking industry.

In this respect it should be noted that nothing prevents spinning of thewheel member 10 within either of the rims 20 or 26 except the pressurethat can be developed by the clamps 18 against the outboard shoulder 28and the resulting pressure developed between the inboard rim shoulder 22and the wheel shoulder 12. The possibility of a free-spin conditionbetween the wheel member and either or both of the dual rims makes itvitally important that the rim clamps be assembled snugly and withoutcocking against the rim assembly.

Referring now to my present invention, FIGS. 3, 4 and 5 illustrate thepreferred embodiment of this invention.

Reference numeral 100 designates a wheel member which is conventionalexcept in one respect to be later described. The wheel member 100 thushas a conventional radially outwardly projecting inboard shoulder 102,an annular cylindrical guiding surface 104, and peripherally spacedaxially extending spokes 106 located to the outboard side of the wheelmember 100. As has become the practice in the industry, the spokes 106are five in number, although only one appears in the drawing.

The spokes 106 differ from those found in conventional wheel members byreason of having axially extending outboard extensions 108 thereon. Theextensions 108 have upper surfaces 109 which are cylindrically curvedand represent segments of a cylinder of revolution generated about theaxis of rotation for the wheel member 100.

Likewise, the spokes 106 have cylindrically curved radially outersurfaces 107 which also represent sections of a cylindrical surface ofrevolution generated about the axis of rotation for the wheel member100. For reasons which will later become more apparent, the radius aboutwhich the surfaces 107 are generated is larger by a predetermined amountthat the radius about which the surfaces 109 are generated.

As with the prior art structure of FIG. 1, the preferred embodiment ofthe present invention includes an inboard rim 1 12 having an inwardlydirected shoulder 114 which interfits the wheel shoulder 102, andoutboard rim 118 having a radially inwardly directed shoulder 120 and aspacer 1 16 which establishes a predetermined separation between therims 112 and 118. This rim and spacer construction, being conventional,requires no further description in this application.

The rim clamp for the present invention is designated by the referencenumeral 1 in FIG. 3 and is more fully illustrated in FIGS. 4 and 5. Thisclamp, which is generally of an L-shape in cross-section, comprises afirst leg 122, and a second leg 126 disposed substantially at a rightangle to the first leg. The interior surface of the leg 122 constitutesa cylindrical section generated about a generating axis substantiallyperpendicular to the leg 126 and at substantially the same radius as thepreviously described spoke surfaces 107.

By reason of the manner in which the rim clamp is assembled to the wheelmember 100, it is convenient to refer to the end of the leg 122 whichmost closely approaches the wheel shoulder 102 as the inboard or distalend of the leg 122, and the end of the leg 122 which is integrallyconnected to the leg 126 as the outboard end of the leg 122.

As best appears in FIG, 4, it can be seen that the inboard end of theleg 122 has a beveled outer surface 124 which represents a segment of aconical surface. The surface 124 is generated about the same axis as theinterior surface of the leg 122 and is adapted to snugly interfit theshoulder 120 on the rim 112. The shoulder 120 can be described ascomprising a conical interior wall which interfits the surfaces 124 ofthe several clamps 110.

As also best appears in FIG. 4, the leg 126 of the clamp 110 terminateswith an arcuate bearing surface 128. The radius which generates thissurface is substantially the same as the radius which generates thesurfaces 109 on the spoke extensions 108.

The leg 126 also has an oblong aperture 130 therein which is adapted toaccommodate bolts 132 fixedly embedded in each of the spokes 106 andadapted to be threadly engaged by nuts 134. As above noted, the bearingsurface 128 is generated about the same axis and at the same radius asthe surface'109 of the spoke extension 108 and likewise the interiorcylindrical surface of the leg 122 is generated about the same axis andat the same radius as the radially outer surfaces 107 of the spokes 106.It is not to be inferred. from this described relationship between theclamp 110 and the spokes 106 however that the separation between thecylindrical interior wall of the leg 122 and the bearing surface 128 isequal to the separation between the surfaces 107 and 109 of the spokes106. Rather, the length dimension of the leg 126 is sized so that theseparation between the bearing surface 128 and the interior cylindricalsurface of the leg 122 will slightly exceed the separation between thesurfaces 107 and 109 of the spokes 106. This oversize in the leg 126 ispreferably only a few thousandths of an inch and is preferably achievedby assigning tolerances to the design of the clamp 110 which assure thatthe leg 126 will be long enough to locate the bearing surface 128 atleast as far from the interior surface of the leg 122 as is the surface109 from the surface 107 of the spoke 106.

The aperture 130 in the leg 126 is made ovate as shown in FIG. 4 toassure that in all cases within the tolerance limits assigned to thedesign of the clamp 1 10 the bearing surface 128 will bottom against andthus bear against the surface 109 of the spoke to which it is assembled.Thus, the bolt 132 is not permitted to interfere with firm seating ofthe bearing surface 128 against the spoke extension surface 109.

The assembly of the rims 112 and 118 with the spacer 116 onto the wheelmember is evident from an inspection of FIG. 3. Likewise, the assemblyof the rim clamps to the spokes 106 is evident from an inspection ofFIG. 3. Since the leg 126 is oversized as explained, there may be atendency for the bearing surface 128 to lock against the outer end ofthe spoke extension 108 as the clamp 110 is slid into position insidethe rim 1 18. The likelihood of any such lock condition is eliminated inthe present invention by rounding the inboard margin of the bearingsurface 128 as appears at 136 in FIG. 4. For the same reason, theoutboard margin of the surface 108 has been rounded as appears at 138 inFIG. 3. Obviously, as these two rounded margins meet, they readily camone past the other.

It can be further noted in FIG. 3 that the interior cylindrical wall ofthe rims 1 18 and 1 12 is sufiiciently large in relation to the cylinderdefined by the surfaces 107 of the spokes and in relation to thethickness of the legs 122 of the clamps 1 10 that ample room existsbetween the clamps 110 and the interior surface of the rim 118 forcamming of the bearing surface 128 onto the spoke extension surface 109.

As the clamps 110 are assembled onto their respective spokes 106 andadvanced in the inboard direction by tighten ing of the nuts 134, therim 118 is driven into concentric relation to the wheel member 110 byaction of the clamp surfaces 124 against the rim shoulder 120. At thesame time of course the rim 1 12 is driven into concentric relation tothe rotary axis for the wheel member 100 by reason of the rim shoulder 11 interfitting the wheel shoulder 102, To promote a uniform movement ofboth rims to concentricity with the axis for the wheel member 100, it isobviously desirable that the nuts 134 be tightened in substantialuniformity as to all spokes 106, this being the common practice inassembling dual wheels of the type disclosed in the present application.

It should be noted that as the surfaces 124 of the clamps 1 10 aredriven progressively in the inboard direction against the rim shoulder120, the nuts 134 will act against the legs 126 to pivot the clamps 110inwardly toward the center of the wheel member 100 and thus to press thebearing surfaces 128 progressively harder against the spoke extensions108. This action assures that the surfaces 124 of the clamps 110 willmove snugly under the rim shoulders 120 without a cocking of the clamp110 and without cocking of the rim 118 from its desired position ofconcentricity with respect to the rotary axis for the wheel member 100.

It will be noted of course that the legs 122 of the clamps 1 10 aresized to firmly seat the rims 1 12 and 1 18 to their positions ofconcentricity with respect to the rotary axis for the wheel 100 beforethe legs 126 can bottom against the outboard ends of the spokes 106.

Having thus described my invention, I claim:

1. A wheel assembly comprising rim means to support at least one tire, awheel member disposed within said rim means and having inboard andoutboard sides, said wheel member having a radially outwardly projectingwheel shoulder adjacent the inboard side thereof, said rim means havinga first radially inwardly projecting rim shoulder abutting said wheelshoulder, said wheel shoulder and said first rim shoulder being annularshoulders each having a conical surface interfitu'ng a complementaryconical surface of the other, said rim means having a second radiallyinwardly projecting rim shoulder spaced in the outboard direction fromsaid first rim shoulder, said second rirn shoulder being an annularshoulder having a conical wall disposed to the outboard side thereof,said wheel member having a plurality of axially extending spokes at theoutboard side thereof, each spoke having a radially outer axial surface,each spoke having an outboard extension projecting axially therefrom,each extension having a radially outer axial seating surface spacedradially inwardly from the outer surface of its spoke, a plurality ofrim clamps, each clamp comprising a first leg overlying the outersurface of one of said spokes, each first leg having an inboard endseating against said second rirn shoulder and an outboard end, theinboard end of each first leg being a segment of a conical surfaceadapted to interfit the conical surface of said second rim shoulder,each clamp having a second leg attached to the outboard end of its firstleg, each second leg having a bearing surface seating on the seatingsurface of the extension from the spoke overlaid by the first leg of thesame clamp, each second leg having a length causing its bearing surfaceto bear against the seating surface of the extension from the spokeoverlaid by the first leg of the same clamp, and fastener means, therebeing one fastener means for each clamp, adjustably connecting eachsecond leg to one of said spokes, said fastener means being adjustableto draw said second legs in the inboard direction towards said spokesand thereby bias the inboard end of each first leg against said secondshoulder, said outer surfaces of said spokes being sections of a firstcylindrical surface of revolution, and said seat-ing surfaces of saidextensions being sections of a second cylindrical surface of revolutioncoaxial to and smaller in diameter than said first surface ofrevolution.

2. The wheel assembly according to claim 1 wherein the first leg of eachsaid rim clamp has a surface which is a section of a cylindrical surfaceof revolution substantially equal in diameter to said first surface ofrevolution, said surface adapted to confront the outer surface of thespoke to which said clamp is connected.

3. The wheel according to claim 2 wherein said bearing surfaces of saidsecond legs are each a section of a cylindrical surface of revolutionsubstantially equal in diameter to said second cylindrical surface ofrevolution.

l i I III l

1. A wheel assembly comprising rim means to support at least one tire, awheel member disposed within said rim means and having inboard andoutboard sides, said wheel member having a radially outwardly projectingwheel shoulder adjacent the inboard side thereof, said rim means havinga first radially inwardly projecting rim shoulder abutting said wheelshoulder, said wheel shoulder and said first rim shoulder being annularshoulders each having a conical surface interfitting a complementaryconical surface of the other, said rim means having a second radiallyinwardly projecting rim shoulder spaced in the outboard direction fromsaid first rim shoulder, said second rim shoulder being an annularshoulder having a conical wall disposed to the outboard side thereof,said wheel member having a plurality of axially extending spokes at theoutboard side thereof, each spoke having a radially outer axial surface,each spoke having an outboard extension projecting axially therefrom,each extension having a radially outer axial seating surface spacedradially inwardly from the outer surface of its spoke, a plurality ofrim clamps, each clamp comprising a first leg overlying the outersurface of one of said spokes, each first leg having an inboard endseating against said second rim shoulder and an outboard end, theinboard end of each first leg being a segment of a conical surfaceadapted to interfit the conical surface of said second rim shoulder,each clamp having a second leg attached to the outboard end of its firstleg, each second leg having a bearing surface seating on the seatingsurface of the extension from the spoke overlaid by the first leg of thesame clamp, each second leg having a length causing its bearing surfaceto bear against the seating surface of the extension from the spokeoverlaid by the first leg of the same clamp, and fastener means, therebeing one fastener means for each clamp, adjustably connecting eachsecond leg to one of said spokes, said fastener means being adjustableto draw said second legs in the inboard direction towards said spokesand thereby bias the inboard end of each first leg against said secondshoulder, said outer surfaces of said spokes being sections of a firstcylindrical surface of revolution, and said seat-ing surfaces of saidextensions being sections of a second cylindrical surface of revolutioncoaxial to and smaller in diameter than said first surface ofrevolution.
 2. The wheel assembly according to claim 1 wherein the firstleg of each said rim clamp has a surface which is a section of acylindrical surface of revolution substantially equal in diameter tosaid first surface of revolution, said surface adapted to confront theouter surface of the spoke to which said clamp is connected.
 3. Thewheel aCcording to claim 2 wherein said bearing surfaces of said secondlegs are each a section of a cylindrical surface of revolutionsubstantially equal in diameter to said second cylindrical surface ofrevolution.